const age = 22;
module.exports.username = "wt";
module.exports.sayHello = ()=> {
    console.log('hello');
}
module.exports.age = age;
// 此操作会覆盖上面的module.exports
module.exports = {
    nickName: 'tom',
    sayLove() {
        console.log("I Love You");
    }
}